Influence of Fluid Shear and Microbubbles on Bacterial Detachment from a Surface

Abstract

Prevention of microbial adhesion and detachment of adhering microorganisms from surfaces is important in many environmental, industrial, and medical applications. Fluid shear is an obvious parameter for stimulating microbial detachment from surfaces, but recently it has been pointed out that a passing air-liquid interface also has potential in stimulating microbial detachment. In the present study, the ability of microbubbles to stimulate detachment of bacterial strains from a glass surface is compared with the effects of fluid flow. Adhesion and detachment of Actinomyces naeslundii T14V-J1, Streptococcus oralis J22, and their coadhering aggregates were studied on glass, mounted in a parallel plate flow chamber. High fluid wall shear rates (11,000 to 16,000 s ؊1 ) were established in a laminar flow regime in the absence and presence of microbubbles. Wall shear rates stimulated detachment ranging from 70% to 30% for S. oralis and A. naeslundii, respectively. Coadhering aggregates were detached up to 54%. The presence of microbubbles in the flow increased the detachment of A. naeslundii within 2 min of flow from 40% in the absence of microbubbles to 98%, while detachment of neither S. oralis nor coadhering aggregates was affected by the presence of microbubbles. In summary, extremely high fluid flows can be effective in stimulating microbial detachment, depending on the strain involved. The addition of microbubbles to the flow allows the detachment of tenaciously adhering bacteria not detached by flow alone, but not of adhering coaggregates.

Gas‐Liquid Mass Transfer in Fibrous Bed Reactor with Counter‐Current Liquid Recycle

“…Consequently, the recycle liquid velocity can be varied over wide margins to gain control over the biofilm thickness. A background analysis referring to such flow procedure has been published recently [21].…”

Removal of Interproximal Dental Biofilms by High-velocity Water Microdrops

“…Fluid shear stress is an alternative mechanical approach for controlling biofilm build-up (Stewart, 2012). Previous studies have demonstrated that if sufficiently high fluid shear stress can be generated, this alone can stimulate biofilm detachment (Rutter and Vincent, 1988;Hope et al, 2003;Sharma et al, 2005a;Paramonova et al, 2009). High-velocity water droplets (Cense et al, 2006) and entrained air bubbles (Parini et al, 2005;Sharma et al, 2005b) have also been shown to be able to remove bacteria and biofilms from surfaces utilizing the additional effect of generating a "surface-tension force" away from the surface by the passage of an air/water interface (Gómez-Suárez et al, 2001).…”

Effect of microbubbled water on the removal of a biofilm attached to orthodontic appliances — An in vitro study —

“…This indicates that microbubbled water has the effect on the tooth surface in a clinical situation. A previous study also showed that microbubbles were very effective to remove S. oralis from the glass plate [19][20] . Therefore the microbubbled water has the potential to prevent dental caries in the mouth of orthodontic patients.…”

“…The detachment of biofilm from the brachet by micro-bubbled water possibly depends on interface velocity, which is generated at gas-water interface 20) . Micro-bubbled water activates the hydrodynamic shear and surface tension forces, which causes the detachment of the biofilm from the orthodontic bracket.…”

“…There are only a few reports on the removal of microorganisms in dentistry. Sharma et al [19][20] reported that Streptococcus oralis was completely removed from salivary pellicles with microbubbled water but Actinomyces naeslundii was not completely removed. No report has so far examined the effect of microbubbled water on the removal of major oral pathogens such as S. mutans and C. albicans, which are among the major components of biofilms attached to orthodontic appliances.…”